Various types of devices for securing a tire to the wheel are in use today. These devices are commonly called “bead locks.” Bead locks secure the tire bead to a wheel rim, preventing the tire from rotating around the wheel when torque is applied, such as during acceleration or breaking. Bead locks also prevent the tire from coming detached from the wheel during operation, and may help preserve the integrity of the tire's pneumatic seal.
Bead locks vary in design according to the type of wheel and tire. For example, bead locks used for off-road 4×4 vehicles often clamp the tire bead area between two ring-shaped plates around the circumference of the tire bead. Alternatively, bead locks used in off-road motorcycles clamp at only one spot on the tire. These bead locks have a U-shaped cup attached to a threaded rod, which is protrudes through the wheel rim and is tightened with a nut. Tightening the nut draws the U-shaped cup down against the inside surface of the tire and clamps it against the rim flange.
These and other types of bead locks are mostly effective for their intended use. However, bead locks currently in use have drawbacks, either in their cost, their ability to hold the tire, or their tendency to unbalance the wheel. Furthermore, all bead lock designs currently in use create design limitations in other areas of the tire and wheel assembly, particularly in the area of tubeless tire sealing on spoked-wheel rims.
External bead locks, such as those used on 4×4 vehicles, require a special wheel with a bead lock system built in, adding significant complexity and expense for the vehicle owner if a bead locking system is desired. External bead locks are not used on motorcycles or bicycles.
Bead locks that secure the tire internally (such as the motorcycle bead lock described above) have drawbacks such as: (1) the tire bead is only secured to the wheel at one point, and does not secure the entire circumference of the bead, and (2) imbalance the wheel, causing wheel hopping and vibration, and (3) obstructs the use of tire and rim sealing devices, which are sometimes used to convert tube-type tires and wheels to be inflatable tubeless.
Another type of internal bead locking system currently in use for 4×4s, motorcycles, and bicycles, is composed of a high pressure bladder positioned between the tire beads and adjacent to the wheel. The bladder is inflated to force the tire beads outward against the wheel flange. With enough pressure, the outward force generated by the bladder can create an effective bead lock. This design has the added benefit of creating an airtight seal between the tire beads, which is sometimes used to enable tube-type tires and wheels to be inflated without an inner tube. A drawback to this design is the internal air bladder is susceptible to leaks and punctures. If the bladder fails, the tire must be unmounted to perform a repair.
There is a clear need therefore for improved bead locking mechanisms designed for use in all types of wheel/tire combinations. In view of the shortcomings of the known and available solutions, the present invention defines a mechanically simple and effective device for locking a tire to a rim and for defining an airtight seal between the tire and the wheel so that even a tire that is designed for use with a tube may be inflated without a tube in a tubeless fashion.